Two and a half days before symptom onset, people may be infectious
You had symptoms or you had not? As of the end of January, the first corona cases were reported in Germany with a Munich-based automotive supplier, broke out had been a discussion of patient 0 – a Chinese business woman who found a training place and the Coronavirus unknowingly more. In first reports it was said that the woman had shown during their stay, no symptoms at all. This was initially interpreted as evidence for asymptomatic Transmission.
Later, however, the denial was followed by the patient herself. You have felt already, in Germany, malaise, and fever reducing remedy is taken, and not, as first reported, on their return flight to China. The question remained: Is the pathogen before the onset of the symptoms of the disease infectious?
Corona
Viruses – so the inanimate creatures work
At this point, there are already first reports about cases of illness in China, who is apparently in people with no obvious symptoms attached to. International experts were initially skeptical. They suspected: it May be that these people had had contact with a symptomatic sick – without knowing it.
A study from Hong Kong further evidence for asymptomatic Transmission of Sars-CoV-2 now. The study comes from a team of researchers to the clinicians, Gabriel Leung. You have never appeared in any scientific magazine, has not been so examined comprehensively. Like the Berlin virologist Christian Drosten revealed in yesterday’s episode of the NDR Podcasts, he keeps the study, but of high quality. Drosten had already evaluated the data of the Munich patients: “This study has shown that the Virus replicates in the pharynx in the early phase of infection and that the Virus itself is in the earliest smears so highly detectable, that it is on day one and two already on the descending Branch.”
Transmission before symptom onset possible
To get similar results, the Chinese researchers analyzed data from 94 patients from South China’s Guangdong now. “That is to say, the summit of the Virus must be prior to the first day,” says Drosten. Thus, it differs significantly from the well-known Sars-1 exciter: “That was to contain it so well, because it will only be for a long time after symptom onset properly infectious in the average patient.”
The scientists Leung also studied data from 77 pairs in which one of the other infected. The researchers wanted to know: How long is the period of time from symptom onset in the case of a Partner until the beginning of the other is? This interval is called the “Serial Interval” – so series length, so Drosten. This rich in the study in the middle between 5.2 and 5.8 days. Thus, the serial interval spent in approximately the range of the mean incubation time is also specified at 5.2 days. “This tells us that the average Patient is actually waiting just as long on the symptoms after infection, as it needs to transfer this infection between the two patients,” the expert said.
“This does not mean that we have only on the day of symptom onset in the middle of a transmission at the beginning, but probably also in front of it. The average Patient is basically on the day of symptom onset, but this is only the average Patient. Some patients will only be transferred after the onset of symptoms and unfortunately, some of to be transferred prior to symptom onset. This is then a probability distribution that can be calculated.” You can assume that 44 percent of all infection events have occurred before the Infected person was ever sick, so Drosten. He assumes that the infectivity starts in the middle, two and a half day prior to symptom onset.
The result would highlight the importance of distance schemes. Who could only at the first signs of the disease at home to sleep, got infected in the normal social way of dealing with people. With the usual rules of Infection prevention, symptom recognition and isolation – could this disease do not contain it, says the virologist. Instead, people dissociate from each other, I would like the “targeted way”.
Source: NDR Info